実験力学
Print ISSN : 1346-4930
ISSN-L : 1346-4930
19 巻, 1 号
選択された号の論文の9件中1~9を表示しています
解 説
論 文
  • 眞子 巧巳, 西 剛史, 太田 弘道, 助永 壮平, 柴田 浩幸
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 8-12
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

    The thermal effusivities of CaO-SiO2-Al2O3-R2O (R=Li, Na, K) melts were measured by the front-heating front-detection laser flash method. The thermal conductivity was determined from the thermal effusivity, specific heat capacity and density. The specific heat capacity was evaluated based on the additive law, using the liquid state of respective oxides in literature values. The density was measured using Archimedes principle at room temperature in a glassy state. As a result, it was found that the thermal conductivity of CaO-SiO2-Al2O3 melt was lower than those of CaO-SiO2-Al2O3-R2O (R=Li, Na, K) melts. It was also found that the NBO/T dependence of thermal conductivities for CaO-SiO2-Al2O3-R2O (R=Li, Na, K) melts was negative. On the other hand, there was no clear relation between the thermal conductivity and the viscosity.

  • 霜降 真希, 平井 義和, 土屋 智由, 田畑 修
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 13-18
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

       Nanogap is expected to be applied to thermionic generation. However, the nanogap fabricated by microfabrication technologies have small area and non-parallel rough surfaces. In this research, we fabricated nanogap by cleaving single crystal silicon beam on (111) plane with silicon-on-insulator microelectromechanical system (SOI-MEMS) device and obtained nanogaps with 40 nm - 1.47 μm distance gap and parallel smooth surfaces of 28 - 40 μm2. Temperature difference between nanogap was measured using Raman microscope for evaluation of thermal transfer coefficient via nanogap. As a result, 45.0 - 61.9 K temperature difference was observed, and it was confirmed that the thermal transfer coefficient is significantly small. This indicates that the fabricated nanogaps were successfully formed and not in contact, and these methods are useful to evaluate the thermal properties of nanometer scale vacuum space.

  • 三宅 修吾, 永井 明里, 山田 海斗
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 19-23
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

       In this paper, we report a developed high-sensitive isothermal calorimeter for a small amount of pulverized Al/Ni multilayer material with a self-propagating exothermic reaction. Since instantaneous heating is generated by initiating an exothermic reaction in Al/Ni multilayer powder, we designed the calorimeter equipped with electric probes for initiating the reaction. The thermal equilibrium state of the calorimeter is very fine within ±0.01 K, it is realized by high adiabaticity of the reaction vessel and using a high sensitive thermistor. We demonstrate the availability of the calorimeter by measuring the temperature change of the reaction cell involving the Al/Ni multilayer powder fabricated by cold-rolling and pulverizing method. The observed time-temperature curves provided direct temperature rising by the exothermic heat. Estimated exothermic heat of the Al/Ni multilayer powder is approximately 768 J/g in 20 passes of cold-rolling and 1107 J/g in 40 passes.

  • 土屋 智由, 鈴木 淳也, 片岡 達哉, 平井 義和, 菅野 公二, 田畑 修
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 24-29
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

       A method to measure the strain of a single-walled carbon nanotube (SWCNT) under tensile load using mirco Raman spectroscopy is reported. The method includes a micro-electro-mechanical system based tensile test stand (MEMTES) with a thermal actuator, assembly using dielectrophoresis and clamping by electroless gold deposition. The MEMTES was fabricated from a silicon-on-insulator wafer, whose device layer of 5-μm thick was used as the test stand structure. It applies tensile load to SWCNT more than 10% in strain. SWCNT was assembled by applying ac voltage at the gap of MEMTES and was fixed by covering gold thin film through electroless deposition. Raman spectra were measured while an assembled SWCNT was being loaded by actuating the Chevron-type thermal actuator. As a result, we observed a downshift of the G+-band and the change was -2.1 cm-1/% to -4.1 cm-1/% against the tensile strain up to 2 %. Due to bundling of SWCNT and insufficient fixing force at the ends, the downshift was decreased at the strain more than 2% and the tensile strength was not measured.

  • 山本 梨乃, 三宅 修吾, 金築 俊介, 生津 資大, 後藤 大輝, 訓谷 保広, 小金澤 智之
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 30-37
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

       Energy saving and reduction of jisso defect are important in the manufacturing process of MEMS and various electronic devices. As one possibility, a new heat source is required for joining process of electronic components. In this situation, we are studying an exothermic characterization of an Al / Ni multilayer materials, which can generate huge exothermic heat by given a small energy such an electric spark. In this paper, we report the relationship between the rolling condition and the exothermic characterization of the Al/Ni multilayer material. It was found that, the maximum temperature rises as the rolling ratio and rolling pass increased. In addition, it was revealed that the generated intermetallic compounds (IMCs) and the generation process were different depending on the rolling condition by High-precision crystal structure analysis and Time-resolved X-ray diffraction. NiAl having the highest enthalpy of formation was dominant in samples with the highest temperature, and it was formed in a short time. From these results, it is inferred that the stacked structure of the Al / Ni multilayered powder material greatly affects the reactivity. Particularly, it was found that, thinning and multilayering is very important of reaction of the Al/Ni multilayer material.

  • 前川 夏菜, 金築 俊介, 後藤 大輝, 生津 資大
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 38-43
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

       In this paper, we describe the effect of controlling reacted NiAl and solder bond interface on bending strength of Al/Ni-reactively-soldered single-crystal Si specimens. The exothermic reaction in Al/Ni multilayer film was used to melt SnAg-solder film for producing Si solder joint. After the instantaneous bonding, Si rod-shaped specimens with the bonded section was prepared by mechanical dicing. Four-point bending test was then conducted to investigate the bending strength and the weakest layer or interface in the bonded section. The specimens with Al/Ni multilayer film deposited in the Al→Ni→…→Al→Ni order fractured at the base-side solder-NiAl interface. By changing the deposition order to Ni→Al→…→Al→Ni, the bending strength of the specimens increased and the fracture origin changed. With the usage of the free-standing film, bending strength increased more. The improvement of mechanical reliability would be caused by a reduction of the number of voids at the solder-NiAl interface.

論 文
  • 二宮 広樹, 吉岡 修哉
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 44-51
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

       New wind turbine blade designed exclusively for vertical axis wind turbine (VAWT) is examined. This new blade has "Magatama" type cross section. In this paper aerodynamic force generated by the Magatama blade in two dimensional potential flow is experimentally investigated by using Hele-Shaw cell. Pressure distribution and aerodynamic force are calculated from streamlines visualized in the Hele-Shaw cell. As a first step, potential flow around circular cylinder and Joukowski airfoil is examined. Obtained pressure distributions are in good agreement with theoretical values. Increase of lift force with increase of angle of attack is also confirmed by examination of NACA0018 airfoil. Our original Magatama blade is then investigated by the Hele-Shaw cell. Pressure distribution and aerodynamic force are successfully obtained. It is confirmed that the lift force can be controlled by modifying curvatures of upper and lower surface of the Magatama blade.

  • 山田 涼平, 山本 裕介, 吉岡 修哉
    原稿種別: 研究論文
    2019 年 19 巻 1 号 p. 52-59
    発行日: 2019/04/22
    公開日: 2019/04/25
    ジャーナル フリー

       A new wind turbine blade which has Magatama-type cross section is investigated. This blade is exclusively developed for vertical axis wind turbine (VAWT). It is expected that VAWT with this Magatama-type blade is able to operate in low wind speed condition. Numerical simulation is first attempted as a preliminary test to determine the configuration of the cross section of the Magatama blade. Intensive wind tunnel tests are then executed to investigate detailed other conditions to operate as a VAWT. Performance of VAWT with Magatama blades and that with conventional NACA0018 blades are compared by wind tunnel experiments. Results show the VAWT with Magatama blades effectively works and generates power in low tip speed ratio condition as compared with the VAWT with conventional NACA0018 blades. Angle of blades is usually set at drag-type or lift-type position on its rotor in conventional VAWT rotor case. On the other hand, VAWT with new Magatama blade generates maximum power when the Magatama blades are set at angle between conventional lift- and drag- type position. Pressure and velocity distributions around the blade on rotating rotor indicate this is caused by effective lift force generated by Magatama blade in backward side of azimuth position in low tip speed ratio condition.

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